In the conventional weaving of fabric on a shuttleless loom or a fluid jet loom, a weft yarn is repeatedly inserted from one side of the woven cloth to the other, the inserting motion being known as a picking motion. One or both ends of the inserted weft yarn are then cut by a cutting device and the opposite side ends of the weft yarn are left hanging out of the selvage portion of the woven cloth. Such hanging yarn ends may frequently be reinserted during a subsequent pick into the structure of the woven cloth, with the result being a faulty pick and/or a damaged selvage.
A known technique for preventing such problems is to provide an additional selvage (known as a catch-cord or waste binding yarn) alongside the existing selvage of the woven cloth, which additional selvage is utilized for grasping and holding the severed ends of the inserted weft threads. The inserted wefts are cut at the intervening portion between the cloth selvage and the additional selvage, and after trimming and twisting of this additional selvage the catch-cord is pulled or drawn off the loom and collected in a waste receptacle. The catch-cords are either discarded, or in some instances used for making novelty fabrics.
The catch-cords should be drawn from the loom under the same tension and thus the same speed as the woven fabric as it is taken off the loom by the take-off roll. Prior art means for drawing the catch-cords is to mount a pair of cooperating rotatable spur gears on the loom, between which gears the catch-cord is nipped and drawn by a rotation thereof at a speed greater than the fabric take-up roll. Such a structure has created problems related both to: (1) maintaining a proper tension on the catch-cord; and (2) preventing the entanglement of the catch-cord in the drawing gears. With the advent of looms of higher speeds these problems are amplified. With regard to maintaining a proper tension on the catch-cord, if the tension in the drawing rate of the catch-cord is not properly controlled, it may lead to imperfections in the fabric, to faulty cutting of the selvages on the fabric, and/or the breaking of the catch-cord. Improper tension control is frequently caused by the connecting means (generally a balt) between drive shaft for the take-up gears and the pulleys fabric take-up mechanism. Most known structures include a complex arrangement of gears, pulleys, belts, and/or sproket chains which connect the drive shaft for the catch-cord take-up roll to the loom drive. Further, intentionally turning the drive roll faster than the take-up roll causes greater, and thus undesirable, tension in the catch-cord.
The problems with respect to entanglement of the catch-cord in the take-up gears is obvious. Entanglement will cause a variation in tension on the catch-cord and result in imperfections in the fabric and/or jam the take-up gears such that the catch-cord is not pulled off at all. Such problems not only may result in imperfections in the fabric, but in costly down time and repair time for equipment.
The present invention is directed to a highly improved means for drawing the catch-cord selvage from a shuttleless or particularly a fluid jet loom. The improved catch-cord drawing device comprises a pair of smooth surface, cooperating roller members which draw the catch-cord therethrough under the same tension as is applied to the fabric. The cooperating roller members comprise an idler roll and a drive roller which is driven by a shaft that is in turn positively driven by the fabric take-up roll on the loom that applies tension to the fabric for pulling it off the loom. A simple arrangement of meshing gears operatively connects the rotating fabric take-up mechanism to the shaft that drives the catch-cord drive roller. The gear ratios are such that the surface speed of the drive roller is the same as the surface speed of the fabric take-up roll. This arrangement is preferred over the previously known arrangement of driving the drive roller at a speed greater than the fabric take-up roll. The smooth rollers obviously will prevent the type of entanglement that was a common occurrence when spur gears were used.
The surface speed of the drive roller is synchronized to be the same as the speed of the fabric take-up roll such that the catch-cord is drawn from the loom at the same speed as the fabric. This arrangement, as opposed to prior devices which run the catch-cord take-up at a speed slightly faster than that of the fabric, matches the tension on the catch-cord with that of the fabric which aids in the trimming of the catch-cord selvage and substantially eliminates imperfections resulting from improper tension on the catch-cord. In order to make adjustments in the speed of the drive roller and the tension on the catch-cord, the drive roller is mounted on its shaft by means of a slip-fit mechanism. This slip-fit mechanism allows the roller, which fits relatively loosely on its mounting shaft, to be tightened to run at the same speed as the shaft or slightly slower.